1. Field of the Invention
The present disclosure relates to a network scheduler and a network scheduling method thereof, and more particularly, to a network scheduler for effectively managing network bandwidths by selectively supporting a work conserving mode to network entities using an improved token bucket scheme, and a method for limiting network bandwidths in the network scheduler.
This work was supported by the IT R&D program of MIC/IITA [Work Management Number: 2005-S-119-03, The development of open S/W Fundamental Technology]
2. Description of the Related Art
The terminology “network traffic control technology” is generally used in a variety of fields associated with network. A traffic control technology is widely used in a variety of communication fields. The traffic control technology often refers to a technology that enhances an overall network performance by appropriately controlling traffics in a gateway or a router according to situations of a current network traffic.
In addition to a network quality of service (QoS) management technology used in a gateway or a router, a rate limit technology has been proposed which enables a manager to control a network environment. The most famous rate limit technology is a token bucket algorithm. According to the token bucket algorithm, a certain amount of tokens corresponding to a bandwidth is supplied to each entity intending to limit a network bandwidth at constant intervals. When the current remaining tokens are enough to process a packet intended to process, a network scheduling unit (NSU) processes the corresponding packet. On the other hand, when the current remaining tokens are insufficient, the NSU waits until it is refilled with tokens. In this way, the NSU uses a designated network bandwidth.
According to the token bucket algorithm, since an NSU cannot use a bandwidth exceeding the designated bandwidth, an unused idle bandwidth of other NSU is wasted. That is, assuming that 10-Mbps bandwidths are allocated to NSUs A and B, even though the NSU A merely uses 5-Mbps bandwidth, the NSU B cannot use an unused 5-Mbps bandwidth of the NSU A. In some cases, it may be necessary to statically allocate specific network bandwidths to the respective NSUs. However, like the above-described case, there is also a case that it may be necessary to borrow an idle bandwidth of other NSU.